I have about 25GB filled on my 30GB iPod. It's ~2200 songs, podcasts, and all my pictures. It's nice to be able to carry around my whole Pictures folder and show them to family & friends, especially when visiting. Yeah, I don't listen to all of the music, but like the assurance that when I hit "Shuffle", I'll get a great variety that's never boring. Also have playlists for every occasion and keep all the songs I own on there for that reason as well (i.e. workout, running, party, playin cards, romantic, relaxing, pissed off, 80s, 90s, etc, etc).
I'd love a high capacity flash based iPod though, the lag from the HDD gets annoying and I hate worrying about jolting it to much when working.
Good job Apple. BTW, my battery is about to hit the 2 years mark and is taking longer to charge, but ok performance wise.